The Screen object has been supported since Internet Explorer 4.0 and Netscape 3.0 back in 1996. It can be used to determine details about the users screen size and colour depths etc. This can prove useful if content positioning relies on the size of the users screen.
Properties of
window.screen.
availHeight
The availHeight
property returns a value representing the available
height of the users screen. This is the height
property, minus
that taken by any toolbars (i.e. the taskbar)
availWidth
The availWidth
property returns a value representing the available
width of the users screen. This is the width
property, minus
that taken by any toolbars (e.g. the Office toolbar)
availTop, availLeft
The top and left edge of the current screen area. Nonstandard, use
bufferDepth IE ONLY!
The bufferDepth
property can be used to set an off screen buffering
value. Setting the bufferDepth
to "0", no explicit buffering
is set and the
colorDepth
property is set to the screen depth. If bufferDepth
is set to
"-1" (the default), then off screen buffering is performed at the current
screen depth and the colorDepth
property matches the screen
depth.
The bufferDepth
property can be set to 1, 4, 8, 15, 16, 24 or
32, which then causes off screen buffering to occur at the set bit-per-pixel
depth. i.e. bufferDepth=8
performs buffering at 8 bits per pixel,
which is 256 colours. Setting the bufferDepth
to any other value
causes it to be set to "-1".
Note that when bufferDepth
is "-1", if the user changes their
system settings, the bufferDepth
is automatically changed to
the new screen depth.
colorDepth
The colorDepth
property is read-only and reflects the users
current system color depth settings, in bits-per-pixel. I.e. 256 colours,
colorDepth=8
, 16.7million colours, colorDepth=16
.
Note that the colorDepth
property is dependent on the
bufferDepth
property. If bufferDepth
is set to
0 or -1, then colorDepth
is equal to the bits-per-pixel value
of the users system settings. However, if the bufferDepth
has
been explicitly set to a different value, then the colorDepth
property is equal to the bufferDepth
property.
fontSmoothingEnabled
IE ONLY!
The fontSmoothingEnabled
property returns a boolean value indicating
whether the user has font smoothing enabled on their system or not.
height
The height
property reflects the users current screen height,
in pixels.
updateInterval IE
ONLY!
The updateInterval
property can be used to set (in mSec), the
time between updates for the current viewing window. This is only really
a problem when large (size or amount) moving, or continually refreshing images
are present in a page.
setting updateInterval=0
resets the screen update Interval to
its default setting, chosen by Internet Explorer.
width
The width
property reflects the users current screen width,
in pixels.
Methods
The Screen Object has no methods.
Events
The Screen Object has no events.
© 1995-1998, Stephen Le Hunte